Basic hydroxides are formed with the liberation of hydrogen when the alkali metals lithium, sodium and potassium react with water. Two equivalent weights of each reactant are required to produce hydrogen in its diatomic form.
2Li+2H2Oxe2x86x922LiOH+H2↑
2Na+2H2Oxe2x86x922NaOH+H2↑
2K+2H2Oxe2x86x922KOH+H2↑
In the invention, the hydrogen produced in these reactions is used as a fuel source in a fuel cell and the liquid product of each reaction is employed as an electrolyte to produce electron flow between anode and cathode electrodes emersed in the alkaline solutionxe2x80x94as in the instance of the Edison Cell which employs a potassium hydroxide solution.
Other elements such as the alkaline earths, magnesium and calcium, react with water to produce hydrogen but with greater difficulty, requiring the application of heat. In the detailed description in this application only the alkali metals are shown to be of practical interest and the discussion will be centered upon the use of sodium because of its greater abundance in nature.
The invention is a consumable electrode comprised of alkali metal particles in a dispersed phase within an inert heavy liquid medium that is applied by roller, or by other means, to the center surfaces of an inert flexible tape. A cover tape is then placed on top of the first tape containing the dispersion and both tapes are sealed together at their contacting edges forming a consumable electrode, hereinafter called the electrode. The finished electrode is then wound upon a spool in a dispensing cartridge or folded in layered form within a magazine dispenser. In operation, the tensile load on the electrode in the rolled package is nearly constant during its transit through the electrolyte in the reaction chamber, whereas the tensile load in the layered package is dynamically intermittent and higher, but it has the advantage of more efficient utilization of packaging space.
In some designs, particular in the larger electrode construction, a drying agent such as diatomaceous earth or calcium or silica powders may be applied upon the dispersion surface to facilitate manufacture and to promote, by capillary action or surface adsorption, migration of water into the electrode when emersed in the electrolyte. Because of the high heat of reaction when greater quantities of the dispersion are employed an inner glass cloth tape is employed for higher tensile strength of the electrode and to facilitate in holding larger quantities of the metallic dispersion in place during the manufacturing process.
Sealing the lower tape containing the metallic dispersion with the cover tape together at their edges in this manner forms a flattened tubular structure with the alkali metal reactant within. Therefore it is easily seen by those skilled in the art that the consumable electrode described in the application can also be manufactured as a plastic tubular structure by filling it with the dispersion through hydraulic means using a pump or vacuum to induct the dispersion into the tube. The method of manufacturing the tubular construction of the electrode does not effect the proprietary nature of this application.
Present methods used by others to supply hydrogen to a fuel cell employ methane gas reformers or methanol reformers, and in other instances by high pressure storage bottles or by cryogenic storage at xe2x88x92450xc2x0 F. The reforming methods require high temperatures necessary to crack the fuel molecule and strip off the hydrogen component leaving a carbon residue which must be disposed of. Pressure bottle or cryogenic storage of hydrogen raise concerns of leakage in home garages, where most household water heaters are located, or in indoor communal parking areas of hotels and apartment complexes where building fires may occur. In the invention described in this application hydrogen is not present until there is a demand for its generation and immediate usage. Hydrogen is generated directly from the water and no carbon residue is formed except that which is in the tape and dispersion medium and this is continually processed into the spent electrolyte. The water of the electrolyte comes from the fuel cell which facilitates its service during refueling.
The bonding strength of an alkali metal with the hydroxyl ion is much lower than that of its corresponding halide bond. For this reason the reduction of the fused hydroxyl salt of an alkali metal to its base metal is more economic than that of its halide salt. As an example, sodium hydroxide melts at 318.4xc2x0 C. and sodium chloride melts at 800.4xc2x0 C. It is evident that the production of metallic sodium by high temperature electrolyses is more economical from its hydroxide than from its halide salt. To reduce the cost of fuel cell operation by use of a consumable electrode it is prudent that the expended electrolyte, in the reaction cell of the invention to be described, be recovered for recycling during replacement of the consumable electrode cartridge during refueling.
The invention is an electrochemical method of supplying hydrogen and electrons to a fuel cell. The design uses a reactive sodium electrode, hereinafter called a consumable electrode. The consumable electrode is formed as a sodium dispersion that is applied by continuous roller application, or by other means, upon a tape, or by hydraulic induction into a tubing, both tape and tubing being sufficiently flexible such that they may be wound upon a spool for insertion in a dispensing cartridge that feeds the consumable electrode into a caustic electrolyte solution. The quantity of hydrogen and electron flow generated by this means is approximately proportional to the feed rate of the consumable electrode into the electrolyte and to the quantity of the dispersed sodium metal reacted.
The primary objective of the invention is to provide a method of hydrogen generation for use in automotive fuel cells and other types of mobile equipment.
It is another object of the invention to show a means of servicing the fuel cell with a new consumable electrode dispensing cartridge by quick-disconnect mechanism, replacing the expended cartridge at a fuel station.
It is yet another object of the invention to provide an additional supply of electrons to a storage battery or directly to the fuel cell by hydrolysis of the sodium within the consumable electrode with the water content of the electrolyte that produces a migration of charged ions moving between the poles of the cathode and anode of the consumable electrode cartridge.
It is still another object of the invention to show a means of scavenging the expended electrolyte for reclaiming its sodium content.